Over the past decade, there has been a surge of interest in block copolymers, as well as microparticles and nanoparticles of these block copolymers. These block copolymers are made of synthetic polymer blocks such as polystyrene, poly(ethylene oxide), polyglycolide, polylactide, and polycaprolactone. Examples of the copolymers include polystyrene-co-vinylpyridine, polystyrene-co-polyethylene, polystyrene-co-polylactide, polystyrene-co-polyisoprene, polystyrene-co-polyacrylic acid, poly(ethylene oxide-aspartate), and polycaprolactone-co-polyamide. See, e.g., Forster et al., J. Chem. Phys., 1996, 104, 9956-9970; Ma et al., J. Am. Chem. Soc., 2001, 123, 4627-4628; Talingting et al., Macromolecules, 1999, 32, 1593-1601; Kwon et al., J. Control. Rel., 1994, 29, 17-23; and Stolnik et al., Adv. Drug Deliv. Rev., 1995, 16, 195-214.